相变混合存储系统管理策略与实现技术

发布时间：2018-05-31 02:11

本文选题：相变存储器 + 损耗均衡算法　；参考：《华中科技大学》2012年硕士论文

【摘要】：随着半导体制造工艺技术的发展，DRAM与闪存的尺寸已经缩小甚多，但进一步缩小的空间不大，且其存储性能随着密度的提升而受到严重影响。在此背景下，研究开发理想的半导体存储器来解决现有存储器技术所面临的瓶颈刻不容缓。为此，新一代具有高密度、高速度、长寿命的存储器——相变存储器应运而生。相变存储器兼具RAM与闪存的优点，其耐写次数虽能达到108，但在理想条件下，一个基本的相变存储系统也仅有几年的寿命。若对同一相变存储单元进行不间断地写操作，则其在数秒内可能失效。鉴此，，提出了一种针对相变存储器的管理策略来提高整个存储系统的寿命。在分析现有闪存和相变存储器管理策略的基础上，提出一种易于硬件实现、低内存消耗的动态交换均衡策略。接着给出混合相变存储系统的硬件架构，分析文件系统到外存系统之间的数据流结构，将系统的元数据与用户数据分离，分别存储到PCM与NAND Flash中。其中，主要对存放元数据的相变存储器的管理策略进行设计和实现，其基本思想是将存储系统划分为多个区域多个阵列，并将文件数据以条带化方式进行存储；通过邻行拷贝算法来交换阵列内相邻的存储行和“冷热区”的数据，以均衡整个系统的写次数。这种算法与现有的方法相比，能加大数据地址映射的离散度，有效抵御重复写相同单元的操作，从而延长存储系统的寿命和利用率。最后，通过仿真结果分析和比较，验证了所实现算法的性能优势。
[Abstract]:With the development of semiconductor manufacturing technology, the size of DRAM and flash memory has been reduced a lot, but the space for further reduction is small, and its storage performance is seriously affected with the increase of density. Under this background, it is urgent to develop the ideal semiconductor memory to solve the bottleneck of the existing memory technology. Therefore, a new generation of high density, high speed, long life memory-phase change memory came into being. Phase change memory (PCM) has the advantages of both RAM and flash memory. Although its write resistance can reach 108, under ideal conditions, a basic phase-change memory system has only a few years of life. If the same phase change memory cell is continuously written, it may fail in a few seconds. Therefore, a phase change memory management strategy is proposed to improve the lifetime of the whole storage system. Based on the analysis of the existing flash memory and phase change memory management strategies, a dynamic switching equalization strategy, which is easy to implement in hardware and low memory consumption, is proposed. Then the hardware architecture of the hybrid phase change storage system is presented. The data flow structure between the file system and the external storage system is analyzed. The metadata of the system is separated from the user data and stored in PCM and NAND Flash respectively. The management strategy of phase change memory which stores metadata is mainly designed and implemented. The basic idea is to divide the storage system into multiple regions and arrays, and store the file data in a striped way. The adjacent line copy algorithm is used to exchange the data of the adjacent storage lines and the "hot and cold zone" in the array to equalize the write times of the whole system. Compared with the existing methods, this algorithm can increase the dispersion of the data address mapping, resist the operation of the same unit repeatedly, and prolong the life and utilization of the storage system. Finally, through the analysis and comparison of the simulation results, the performance advantages of the proposed algorithm are verified.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TP333

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